#include <iostream>
#include <map>
#include <algorithm>
using namespace std;

int main() {
	int ha, hb, hc;
	cin >> ha >> hb >> hc;
	map<int, char, greater<int>> mp({{ha, 'A'}, {hb, 'B'}, {hc, 'C'}});
	for (auto x : mp) cout << x.second << endl;
}